The benzopyrano[4,3,2-cd]indazole ring system is new and is illustrated by the formula ##STR1##
The benzothiopyrano[4,3,2-cd]indazole ring system ##STR2## is known from F. Ullman and Otto van Glenck, Ber., 49: 2489 (1916) and from U.S. Pat. No. 3,505,341 to Elslager et al.
The benzoselenino[4,3,2-cd]indazole ring system is new and is illustrated by the formula ##STR3##